Francis went worth brewster



(No Model.)

' I. W. BREWSTER.

ADJUSTABLY WEIGHTED CENTER BOARD.

Patented June 19, 1894.

WITNESSES.

m! NATIONAL UTNDGRAPHXNG cmAPAuY.

WASHINGTON, n. c.

UNITED STATES PATENT QFFICE.

FRANCIS WENTWORTH BREWSTER, OF BOURNEMOUTH, ENGLAND.

'ADJUSTABLY-WEIGHTED CENTER-BOARD.

SPECIFICATION forming part of Letters Patent No. 521,494, dated June 19,1894. A plication filed February 19, 1894. Serlalllo. 500,631. (Nomodel.)

To all whom, it may concern.-

Be it known that I, FRANCIS WENTWORTH BREWSTER, a subject of the Queenof Great Britain and Ireland, and a resident of Bournemouth, Hampshire,England, have invented an Improved Adjustably-Weighted Center- Board, ofwhich the following is a specification.

This invention relates, to the ballasting of center-boards or drop-heelsused in yachts and the like, and consists in the combination with thecenter-board of adjustable ballast adapted to automatically shift alongthe lower edge or part of the center-board both upon the lowering andupon the raisingof the center-board, so that the ballast will alwaysoccupy its lowest and most useful position whether the center board beup, down or at any intermediate position.

In the accompanying drawings, Figure 1, represents, in sectionalelevation, the keel of a yacht and the center-board trunk, and inelevation, a center-board embodying the pres ent improvements. Fig. 2,represents a sectional plan, with the top of the trunk removed. Fig. 3,represents a sectional elevation on the line 1, 2, Fig. 1. Fig. 4represents an elevation of Fig. 3, the near sides of the trunk and ofthe keel and ballast carrying bulb being removed. Fig. 5, represents alike view to Fig. 4, of a modification, and Fig. 6, represent-s asectional elevation of a further modification.

a, is the center-board, which is pivotally supported at a, in a trunk b,and is lowered and raised as required by a chain a guided by a sheave orpulley a all in a usual manner. To the lower and after edge or part ofthe center-board, I apply a ballast-carrying tubular closed bulb c, ofan angular formation (Figs. 1, and 6) or of an equivalentcur-vedformation in side view, and preferably of an elongated elliptical ordouble convex forma tion in transverse section (Fig. 3). The tubularclosed formation of the bulb enables it to contain the shifting ballastd, with an unimpeded facility of shifting as the manipulation of. thecenter-board may occasion; its angular formation enables such ballast toshift to the respectively lowest part of the centerboard when raised orwhen lowered or when at any intermediate position; and its ellipti=center-board so that the latter will be continued longitudinally andvertically through the bulb so as to divide its interior into equallateral compartments.

The ballast d, may advantageously. be

made of lead or of other heavy, and preferably inoxidizable metal; andmay be adapted to shift by rolling along the bulb (Figs. 1, 3 and 4) inwhich event, it is made approximately 4 of the cross sectional form ofthe bulb, and circular in side elevation, and is formed with trunnionsd, or adapted with runner-wheels, roller-bearings or antifriction wheelsadapted to rest and roll on or in rails or guide-ways c which may beformed on or secured to the inner sides of the bulb c, and are closed ateach end at a distance from the bulb ends to prevent the ballast fromimpact against the latter. Or, the ballast may be adapted to shift bysliding along the bulb, (Fig. 5,) in which event it is made of anelongated form in side elevation, and is formed, at each side, withextended bearings 01, adapted to slide along rails or guide-ways 0. Or,the ballast may consist of gunshot, quicksilver or other materials ofgreater specific gravity than water and adapted to shift in molecular orliquidlike bulk along the bulb, (Fig. 6,) in which event the guide-ways0, would not be required and the ends of the bulb might be fitted withdash-plates 0 serving to prevent sudden impact of the ballast againstthe bulb ends. The after end of the bulb is preferably fitted with ahinged or sliding and suitably secured cap 0 in order to permit ofaccess being readily obtained to the interior of the bulb when in itsraised position, (wide the dotted lines, Fig. 1,) so that ballast may beadded or removed as required.

The trunk 12, is shaped and the keel e, is slotted as at e, toaccommodate the centerboard and its ballast-carrying bulb, Figs. 1 and2. The keel is also formed with a seating e to accommodate exchangeableweighted boards or metal blocks 6 respectively adapted to close thebulged end of the slot 6 when the bulb b, is down (m'de the full lines,Fig. 1), and when it is up, ride the dotted lines, Fig. 1. The trunk isalso made with a top opening b, through which the bulb can,

be got at, and the boards or blocks a adjusted, and which is normallyclosed by a lid W.

I claim as my invention, in yachts and the like- 1. In combination, apivoted center board or drop keel, and adjustable ballast containedtherein and adapted to automatically shift alongthelower edge or partthereof to the lowest part thereof upon the center board beingrais'edorlowered, as set forth.

2. In combination, a pivoted center board, a ballast carrying tubularclosed bulb of an angular or curved formation secured to the lower edgeor part of the center-board, and contained adjustable ballast adapted toantomatically shift along and within the bulb z 5 to the lowest partthereof upon the centerboard being raised or lowered, and means ofraising and lowering the center-board, as set forth.

3. In combination, a pivoted center board, a ballast-carrying tubularclosed bulb of an angular or curved formation secured to the lower edgeor part of the conter-board and formed with inner rails or guideways,and contained adjustable ballast adapted to automatically roll or slidealong and within the bulb to the lowest part thereof upon thecenter-board beingraised or lowered, and means for raising and loweringthe center board, as set forth.

In testimony whereof I have signed my name to thisspecification in thepresence of two subscribing witnesses.

FRANCIS WENTWORTII BREWSTER.

Witnesses:

ARTHUR ALEXANDER CROZIER, Ton FRANCIS BARNES.

